Quick-on filler neck cap

ABSTRACT

A fuel cap (10) and filler neck fitment (14) for receiving the fuel cap. The fuel cap includes an outer member (18) and an inner closure assembly (20) with seal. The cap and fitment both include lugs (28, 36) which interengage when the cap is moved into a closing position to pressurize the seal determined by an improved overriding ratchet arrangement. During removal of the cap, the outer member moves against a spring action for a predetermined arc before the inner closure assembly is moved to disengage the seal. When the seal is disengaged, the spring action takes up the relative motion. Once removed, the cap is retained by an improved tether (74) assembly. The outer member is connected to the inner annular assembly by an improved structural arrangement which allows the outer member to separate under crash impact.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a U.S. national application of internationalapplication Ser. No. PCT/US98/00863 filed Jan. 16, 1998, which claimspriority to U.S. Ser. No. 60/035,394 filed Jan. 16, 1997.

BACKGROUND AND SUMMARY OF THE INVENTION

This invention relates to filler neck caps, and particularly to arotatable cap for closing the open mouth of a filler neck. Moreparticularly, this invention relates to a filler neck cap engageablewith internal flanges formed in the filler neck to cause the cap to beretained quickly and easily in the filler neck.

Conventional caps for closing the filler neck of a vehicle fuel tanktypically include a closure member carrying a seal for closing andsealing the mouth of the filler neck and a handle for turning theclosure member to mount the closure member and seal in the filler neck.A typical filler neck cap includes a ring-shaped seal made of aresilient gasket material that is compressed between the cap and afiller neck receiving the cap to establish a sealed connection betweenthe cap and the filler neck when the cap is mounted on the filler neck.

Newly manufactured "O-ring" seals of the type used in filler neck capsmeet certain stringent size, elasticity, and hardness (durometer)requirements. Over time, however, O-ring seals, as well as other seals,mounted in filler necks tend to shrink, become less elastic, and smallerin cross section due to "O-ring compression set" which occurs when anO-ring seal is exposed to a compression load over time. Such compressionloading occurs whenever a cap carrying an O-ring seal is installed in afiller neck. Filler neck cap O-ring seals also degrade over time as aresult of normal wear following repeated installations and removals ofthe cap on and from the filler neck.

According to the present invention, a cap is provided for a filler neckhaving an open mouth and an internal mounting flange adjacent to theopen mouth. The cap comprises a handle, a body coupled to the handle forrotation therewith, an annular seal around the body, an externalposition-locator lug appended to the body and arranged to lie inspaced-apart relation to the annular seal, and a spiral-shaped capmounting member appended to the body to lie in a position between theannular seal and the external position-locator lug. The spiral-shapedcap mounting member is adapted to engage against the internal mountingflange of the filler neck upon installation of the body in the fillerneck to retain the cap in the filler neck.

In preferred embodiments, the spiral-shaped cap mounting member has afirst end positioned to lie either adjacent to or in contact with theexternal position-locator lug. The external position-indicator lugincludes an inclined flange guide. The spiral-shaped cap mounting memberincludes an annular cap retainer facing toward the handle and beingadapted to engage against the internal mounting flange of the fillerneck upon installation of the body in the filler neck. The annular capretainer at the first end of the spiral-shaped cap mounting member isarranged to merge into the inclined flange guide on the position-locatorlug.

The body of the cap has a cylindrical exterior surface. Thespiral-shaped cap mounting member is appended to the cylindricalexterior surface. The spiral-shaped cap mounting member is formed toinclude a second end spaced apart from the first end and to have an arclength along the cylindrical exterior surface characterized by a centralangle about one hundred sixty degrees. The body has a cylindricalexterior surface and the spiral-shaped cap mounting member is orientedto wind helically around the cylindrical exterior surface.

The filler neck has an outer end including a cylindrical interior sidewall and first and second filler neck mounting flanges appended to thecylindrical interior side wall and arranged to define first and secondlug-receiving spaces therebetween. The cap preferably includes acylindrical body that is sized to fit into the outer end of the fillerneck and first and second position-locator lugs that are appended to thecylindrical body and arranged to lie in spaced-apart relation to oneanother so that each position-indicator lug is situated to pass throughone of the lug-receiving spaces defined between the first and secondfiller neck mounting flanges during an initial stage of cap installationin the filler neck. The annular seal is positioned to lie around thecylindrical body and engage a flange appended to the cylindrical bodyand an annular outer rim included in the outer end of the filler neckduring cap installation in the filler neck. First and secondspiral-shaped cap mounting members are appended to the cylindrical bodyand positioned to lie between the overlying annular seal and theunderlying position-locator lugs and arranged to engage the first andsecond filler neck mounting flanges to retain the cap in an installedposition in the filler neck and compress the annular seal between theflange appended to the cylindrical body and the annular outer rimincluded in the filler neck.

Additional features and advantages of the invention will become apparentto those skilled in the art upon consideration of the following detaileddescription of preferred embodiments exemplifying the best mode ofcarrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the accompanying figuresin which:

FIG. 1 is an exploded perspective view of a filler neck closure assemblyin accordance with the present invention showing a filler neck carryinga pair of spaced-apart internal mounting flanges and a quick-on capincluding a cylindrical body carrying an O-ring seal and pairs ofexternal position-locator lugs and helical mounting members below theO-ring seal and a handle assembly for rotating the cylindrical bodyrelative to the filler neck during chip installation and removal;

FIG. 2 is a side elevation view of the cap (with portions broken away)and filler neck of FIG. 1 prior to insertion of the cap into the openmouth of the filler neck showing one of the position-locator lugs on thecylindrical body positioned to be passed through a lug-receiving spaceprovided between the first and second filler neck mounting flanges(shown in phantom) formed on a cylindrical interior side wall of thefiller neck and showing positioning a first of the cap mounting membersover the first filler neck mounting flange and a second of the capmounting members over the second filler neck mounting flange;

FIG. 3 is a transverse sectional view taken through the cap along line3--3 of FIG. 2 showing the two spaced-apart, radially outwardlyextending, position-locator lugs appended to the cylindrical body of thecap;

FIG. 4 is a transverse sectional view taken through the cap along line4--4 of FIG. 2 looking down onto a first annular cap retainer formed onthe top of the first cap mounting member and a second annular capretainer formed on the top of the second cap mounting member;

FIG. 5 is top plan view of the filler neck taken along line 5--5 of FIG.2 showing the rounded annular seat for engaging the O-ring seal carriedon the cap, the axially outwardly facing annular outer rims formed onthe top of each filler neck mounting flange, and the two lug-receivingspaces formed between adjacent ends of the filler neck mounting flangesand located one hundred eighty degrees (180°) apart to receive the twoposition-locator lugs appended to the cylindrical body of the cap duringcap installation and removal;

FIGS. 6-9 show the position of the cap at an initial stage of capinstallation on the filler neck;

FIG. 6 is a side elevation view of the cap and filler neck of FIGS. 1and 2 showing the cap as it appears when it is first inserted into themouth of the filler neck and then positioned to "rest" on the fillerneck mounting flanges without engaging the O-ring seal against thefiller neck and showing engagement of annular cap supporters formed onthe bottoms of the cap mounting members and the outer rims formed on thetops of the filler neck mounting flanges to support the cap in aninitial position in the filler neck;

FIG. 7 is a top plan view of the handle assembly of the cap of FIG. 6;

FIG. 8 is a perspective view of the cap and filler neck of FIG. 6, withportions of the cap and filler neck broken away, showing positioning ofa "rear" position-locator lug on the cap in a lug-receiving space formedbetween spaced-apart ends of the two filler neck mounting flanges;

FIG. 9 is a diagrammatic view of the cap and filler neck of FIGS. 6-8showing a "flat development" of the two filler neck mounting flanges,the two position-locator lugs and mounting members on the cap, and thevertical spacing between the O-ring seal carried by the cap and theunderlying seat on the filler neck for engaging the O-ring seal;

FIGS. 10-13 show the position of the cap at a later stage of capinstallation on the filler neck;

FIG. 10 is a side elevation view similar to FIG. 6 showing the cap afterit has been rotated about ten degrees (10°) in a clockwise directionabout its axis of rotation from the initial position shown in FIGS. 6-8and just prior to engagement of the O-ring seal on the cap and theunderlying rounded annular O-ring seal seat at the mouth of the fillerneck;

FIG. 11 is a top plan view of the handle assembly of FIG. 10;

FIG. 12 is a perspective view similar to FIG. 8 showing clockwisemovement of the rear position-locator lug and its trailing cap mountingmember out of the lug-receiving space at the "rear" of the filler neckand toward the second filler neck mounting flange;

FIG. 13 is a diagrammatic flat development view of the cap and fillerneck of FIGS. 10-12 showing engagement of the annular cap supporter onthe bottom of each cap mounting member with the underlying outer rim onthe top of one of the filler neck mounting flanges just before theflange guides on top of each position-locator flanges engage the innerrims on the bottom of the filler neck mounting flanges and the O-ringseal engages the underlying O-ring seal seat on the filler neck;

FIGS. 14-17 show the position of the cap in a normal fully installedposition on the filler neck;

FIG. 14 is a side elevation view similar to FIGS. 6 and 10 showing thecap after it has been rotated further, in clockwise direction, a fewdegrees past the position shown in FIG. 10 to a fully installed positionin the filler neck wherein the O-ring seal is compressed between the capand the filler neck and the inner rims of the filler neck mountingflanges engage the flange guides on the position-locator lugs and thecap retainers on the cap mounting members;

FIG. 15 is top plan view of the handle assembly of FIG. 14;

FIG. 16 is a perspective view similar to FIGS. 8 and 12 showing furtherclockwise movement of the rear position-locator lug and its trailing capmounting member to engage the inner rim of the second filler neckmounting flange;

FIG. 17 is a diagrammatic flat development view of the cap and fillerneck of FIGS. 14-16 showing engagement of flange guides on eachposition-locator lug and the cap retainers on each cap mounting memberwith an inner rim on one of the overlying filler neck flange members tocause the cap to be retained securely in the normal fully installedposition within the filler neck and the O-ring seal to be compressed inaccordance with a predetermined specification to establish a liquid andvapor seal between the cap and the filler neck;

FIGS. 18-21 show the position of the cap in a special installationposition of the cap on the filler neck that may occur if the O-ring sealdegrades over time from its "original equipment" specification;

FIG. 18 is a side elevation view similar to FIGS. 6, 10, and 14 showingthe cap after it has been rotated, in a clockwise direction, a fewdegrees past the normal fully installed position shown in FIG. 10 tocompress the O-ring seal further to a point at which it functions as aneffective liquid and vapor seal between the cap and the filler neck;

FIG. 19 is a top plan view of the handle assembly of FIG. 18;

FIG. 20 is a perspective view similar to FIGS. 8, 12, and 16 showingstill further clockwise movement of the rear position-locator lug andits trailing cap mounting member past a position shown in FIG. 10, whichposition corresponds to the normal fully installed position of the capon the filler neck; and

FIG. 21 is a diagrammatic flat development view of the cap and fillerneck of FIGS. 18-20 showing the further movement of the rearposition-locator lug and its trailing cap member relative to theoverlying filler neck flange member referred to in the description ofFIG. 20.

DETAILED DESCRIPTION OF THE DRAWINGS

More and more vehicle drivers are using the self-service bays atgasoline stations and filling their own fuel tanks. Some people havefound that it is difficult to remove and install a conventional fillerneck cap during refueling. Cap 12 is readily installable on andremovable from filler neck 14 by a user without a lot of effort and isconfigured to establish a sturdy sealed connection between cap 12 andfiller neck 14 consistently during use and to compensate for any O-ringcompression set that may develop over the useful life of cap 12 and itsO-ring seal 34.

A closure assembly 10 in accordance with the present invention isillustrated in FIG. 1. Closure assembly 10 includes a cap 12 configuredto mount on a filler neck 14. Cap 12 includes a cylindrical body 16 andan outer shell or handle 18 configured to provide a hand grip. Fillerneck 14 includes a cap-receiving outer end 20 having an open mouth 22and a fuel-delivery tube 24 coupled to outer end 20. A partition 26formed to include a nozzle-receiving aperture 28 is positioned to lie infiller neck 14 and aperture 28 is sized to receive a liquidfuel-dispensing nozzle (not shown) therein.

In a preferred embodiment, filler neck 14 is made of stainless steel toinclude outlet end 20 and fuel-delivery tube 24 and partition 26 is anoptional insert. In another embodiment, outer end 20 is a metal insertformed to include partition 26 and sized to fit in an open end of afiller neck made of metal or plastics material. It is within the scopeof this invention to mount a cap-receiving outer end 20 includingmounting flanges in accordance with the present invention in, on, or toa filler neck to enable a quick-on cap in accordance with the presentinvention to be mounted on the filler neck quickly and easily by a user.

Outer end 20 of filler neck 14 includes a rounded annular O-ringseal-engaging seat 30 at mouth 22 as shown, for example, in FIGS. 1, 2,and 8. Outer end 20 also includes a cylindrical interior side wall 32extending axially inwardly from seat 30 toward partition 26. Cylindricalinterior side wall 32 is sized to receive cylindrical body 16 of cap 12when cap 12 is mounted on filler neck 14 and annular seat 30 is sized toengage a resilient O-ring seal 34 mounted in an annular groove 36 formedin cylindrical body 16 of cap 12.

Outer end 20 of filler neck 14 is formed to include first and secondfiller neck mounting flanges 38, 40 on cylindrical interior side wall 32as shown, for example, in FIGS. 1, 2, 6, and 8. Filler neck mountingflanges 38, 40 function in a manner described below to support andretain cap 12 in a position closing and sealing open mouth 22 in fillerneck 14. Filler neck mounting flanges 38, 40 cooperate with certainportions of cap 12 to enable cap 12 to be installed in filler neck 14quickly and easily by a user.

An annular outer rim 42 facing in an axially outward direction towardcap 12 is formed on the top of first filler neck mounting flange 38 andan annular inner rim 44 facing in an axially inward direction towardpartition 26 and fuel-delivery tube 24 is formed on the bottom of firstfiller neck mounting flange 38. First filler neck mounting flange 38 isalso formed to include a first end 46 and a second end 48 and to have anarc length along cylindrical interior wall 32 characterized by a centralangle of about one hundred forty degrees (140°).

An annular outer rim 50 facing in an axially outward direction towardcap 12 is formed on the top of second filler neck mounting flange 40 andan annular inner rim 52 facing in an axially inward direction towardpartition 26 and fuel-delivery tube 24 is formed on the bottom of secondfiller neck mounting flange 40. Second filler neck mounting flange 40 isalso formed to include a first end 54 and a second end 56 and to have anarc length along cylindrical interior wall 32 characterized by a centralangle of about one hundred forty degrees (140°).

One role of filler neck mounting flanges 38, 40 is to support cap 12 infiller neck 14 during an initial stage of cap installation and then toretain cap 12 securely in filler neck 14 once cap 12 is installed infiller neck 14. Filler neck mounting flanges 38, 40 also cooperate todefine two spaces for receiving exterior lugs 78, 80 appended tocylindrical body 16 of cap 12 during the initial stage of capinstallation to locate cap 12 properly in filler neck 14 during capinstallation. First end 46 of filler neck mounting flange 38 and secondend 56 of filler neck mounting flange 40 are positioned to lie inspaced-apart relation to one another to define a first lug-receivingspace 58 therebetween as shown, for example, in FIGS. 1 and 5. Likewise,second end 48 of filler neck mounting flange 38 and first end 54 offiller neck mounting flange 40 are positioned to lie in spaced-apartrelation to one another to define a second lug-receiving space 60therebetween. Lugs 78, 80 appended to cap 12 will pass axially throughan entry zone defined by the two lug-receiving spaces 58, 60 formed infiller neck 14 during an initial stage of cap installation in the mannersuggested, for example, in FIG. 1, to position cap 12 properly in fillerneck 14 in the manner described below.

As shown in FIGS. 1 and 2, cylindrical body 16 is formed to include anannular groove 36 receiving a resilient O-ring seal 34. In theillustrated embodiment, O-ring seal 34 includes a rounded annular toplip 62, a rounded annular bottom lip 64, and an annular web 66interconnecting lips 62, 64 and normally positioning lips 62, 64 inaxially spaced-apart relation from one another to define an annular gap68 therebetween as shown, for example, in FIG. 2. It is within the scopeof the present invention to mount filler neck seals or gaskets otherthan O-ring seal 34 on cap 12.

An annular flange 70 is appended to an axially outer edge of cylindricalbody 16 and positioned to overlie annular top lip 62 of O-ring seal 34as shown, for example, in FIGS. 1 and 2. Annular flange 70 functions tourge O-ring seal 34 inwardly against annular seat 30 on filler neck 14during cap installation in filler neck 14 as shown, for example, inFIGS. 14 and 18. O-ring seal 34 is made of a resilient material and iscompressed during cap installation to establish a liquid and vapor sealbetween cap 12 and filler neck 14 as shown, for example, in FIGS. 14 and18.

An annular outer ring 72 is appended to the axially outer edge ofcylindrical body 16 and positioned to engage handle 18. To provide adriving connection between handle 18 and cylindrical body 16, pawl teeth74 are provided on flexible arms 76 included in annular outer ring 72.Pawl teeth 74 cooperate with a suitable drive mechanism (not shown)provided inside handle 18 to provide a torque-override connectionbetween handle 18 and cylindrical body 16. Specifically, the pawl teeth74 and the drive mechanism (not shown) cooperate to provide atorque-override driving connection in the cap-advancing direction toprevent over-compression of O-ring seal 34 during cap-installation. Inthe cap-removal direction, the pawl teeth 74 and the drive mechanismcooperate to provide a direct-drive connection to remove cap 12 fromfiller neck 14. It is also within the scope of the present invention tocouple handle 18 to cylindrical body to establish a direct-driveconnection therebetween in cap-advancing and cap-removal directionswithout using a torque-override system.

A pair of position-locator lugs 78, 80 is appended to an exteriorsurface 81 at an axially inner end of cylindrical body 16 as shown, forexample, in FIGS. 1-3. The position-locator lugs 78, 80 are arranged inspaced-apart relation to one another so that each position-locator lugwill pass through one of the lug-receiving spaces 58, 60 defined byfiller neck mounting flanges 38, 40 during an initial stage of capinstallation. Each position-locator lug 78, 80 includes an inclined(with respect to the horizontal) flange guide 82 and a rounded guideedge 84 depending from flange guide 82 as shown best in FIG. 2.Position-indicator lug 78 is positioned to lie about one hundred eightydegrees (180°) away from position-indicator lug 80 about thecircumference of cylindrical exterior surface 81 as shown in FIGS. 1 and3.

First and second cap mounting members 86, 88 are appended to exteriorsurface 81 of cylindrical body 16 of cap 12 as shown, for example, inFIGS. 1 and 2. Cap mounting members 86, 88 are arranged to support cap12 in filler neck 14 during an initial stage of cap installation asshown in FIG. 6 and retain cap 12 securely in filler neck 14 followingcap installation as shown in FIGS. 14 and 18. Cap mounting members 86,88 are configured to cooperate with filler neck mounting flanges 38, 40to enable cap 12 to be installed in and removed from filler neck 14quickly and easily by a user.

Each cap mounting member 86, 88 is a spiral-shaped (e.g., helical)appendage coupled and oriented to wind spirally (e.g., helically) aroundcylindrical body 16 and its axis of rotation 90. Each cap mountingmember 86, 88 is formed to include an annular cap supporter on a bottomside thereof and an annular cap retainer on a top side thereof asdescribed below.

An annular cap supporter 92 facing in an axially inward direction towardfiller neck 14 is formed on the bottom of first cap mounting member 86and an annular cap retainer 94 facing in an axially outward directiontoward handle 18 is formed on the top of first cap mounting member 86.First cap mounting member 86 is also formed to include a first end 96and a second end 98 and to have an arc length along cylindrical exteriorsurface 81 characterized by a central angle of about one hundred sixtydegrees (160°). First end 96 of first cap mounting member 86 ispositioned to lie adjacent to or in contact with position-locator lug 80to cause annular cap retainer 94 at first end 96 to mate with and mergeinto inclined flange guide 82 on position-locator lug 80.

An annular cap supporter 110 facing in an axially inward directiontoward filler neck 14 is formed on the bottom of second cap mountingmember 88 and an annular cap retainer 112 facing in an axially outwarddirection toward handle 18 is formed on the top of second cap mountingmember 88. Second cap mounting member 88 is also formed to include afirst end 114 and a second end 116 and to have an arc length alongcylindrical exterior surface 81 characterized by a central angle ofabout one hundred sixty degrees (160°). First end 114 of second capmounting member 88 is positioned to lie adjacent to or in contact withposition-locator lug 78 to cause annular cap retainer 112 at first end114 to mate with and merge into inclined flange guide 82 onposition-locator lug 78.

In a presently preferred embodiment, first cap mounting member 86 issized and arranged so that second end 98 lies above and in spaced-apartrelation to underlying flange guide 82 formed on top of position-locatorlug 78 as shown in FIGS. 2 and 4. Likewise, second cap mounting member88 is sized and arranged so that second end 116 lies above and inspaced-apart relation to flange guide 82 on top of position-locator lug80. Such positioning and vertical spacing of the position-locator lugsand the cap mounting members enables (1) the second end 48 of firstfiller neck mounting flange 38 to be passed through a space providedbetween guide flange 82 on position-locator lug 78 and second end 98 onfirst cap mounting member 86 and (2) the second end 56 of second fillerneck mounting flange 40 to be passed through a space provided betweenguide flange 82 on position-locator lug 80 and second end 116 on secondcap mounting member 88 during installation of cap 10 on filler neck 14as shown diagrammatically in FIGS. 13, 17, and 21.

During cap installation, cap 10 is first moved relative to filler neck14 from the position shown in FIG. 1 to the position shown in FIG. 2.Cap 10 is then moved toward filler neck as shown in FIG. 6 to insertcylindrical body 16 of cap 10 into outer end 20 of filler neck 14through open mouth 22 and to engage annular cap supporters 92, 110 oncap mounting members 86, 88.against annular outer rims 42, 50 on fillerneck mounting flanges 38, 40. In this "initial position," cap 10 issupported in a rest position on filler neck mounting flanges 38, 40formed on cylindrical interior side wall 32 of filler neck 14 withoutengaging O-ring seal 34 carried on cylindrical body 16 against annularseat 30 provided around mouth 22 of filler neck 14. At the same time,position-locator lugs 78, 80 included in cap 10 have been passeddownwardly into the lug-receiving spaces 58, 60 formed between fillerneck mounting flanges 38, 40 to locate the position of cap 10 properlyin filler neck 14 during this initial stage of cap installation. Asshown in FIGS. 6 and 7, handle 18 normally occupies an initial"rotational" orientation with respect to filler neck 14 during thisfirst stage of cap installation in filler neck 14. Handle 18 includes agrip portion 99 that passes through axis of rotation 90 and has one end102 at a twelve o'clock position and an opposite end 104 at a sixo'clock position.

Referring now to the "flat development" view shown in FIG. 9, O-ring 34is supported to lie distance 118 above a top surface on annular seat 30upon engagement of annular cap supporters 92, 110 of cap mountingmembers 86, 88 and underlying annular outer rims 42, 50 of filler neckmounting flanges 38, 40. As cap 10 is later rotated in a clockwisecap-advancing direction 120 during cap installation, annular capsupports 92, 110 will slide and cam on annular outer rims 42, 50 underthe weight of cap 10 and applied force provided by the cap installer tourge O-ring seal 34 in direction 122 to engage and seal against annularseat 30 of filler neck 14 as shown, for example, in FIGS. 10 and 13.Once handle 18 has been rotated from the initial position shown in FIG.7 through angle 124 of, for example, about ten degrees (10°) as shown inFIG. 11, O-ring seal 34 has moved in direction 122 closer to annularseat 30 so that O-ring seal 34 now lies distance 126 from a top surfaceon annular seat as shown in FIG. 13. At this point, the O-ring seal 34remains in an uncompressed state and has an effective vertical heightdimension 128 as shown in FIG. 13.

Continued rotation of handle 18 in clockwise direction 120 by a userthrough angle 130 of, for example, about five degrees (5°) as shown inFIG. 15 causes inclined flange guides 82 on top of position-locator lugs78, 80 to enter a ramping zone and engage against inner rims 44, 52 onfiller neck mounting flanges 38, 40 so as to retain cap 10 in a normalfully installed position in filler neck 14. As shown, for example, inFIGS. 14, 16, and 17, the position-locator lugs 78, 80 have been movedmostly out of the lug-receiving spaces 58, 60 formed between the firstand second filler neck mounting flanges 38, 40 to engage inner rims 44,52 on filler neck mounting flanges 38, 40. In the normal fully installedposition in the filler neck shown in FIGS. 14 and 17, O-ring seal 34 hasbeen compressed to assume an effective vertical height 132 as shown inFIG. 17 and establish a liquid and vapor seal between cap 10 and fillerneck 14.

A typical filler neck cap includes an O-ring seal made of a resilientgasket material that is compressed between the cap and a filler neckreceiving the cap to establish a sealed connection between the cap andthe filler neck when the cap is mounted on the filler neck. Newlymanufactured O-ring seals of the type used in filler neck caps meetcertain stringent size, elasticity, and hardness (durometer)requirements. Over time, however, O-ring seals mounted in filler neckstend to shrink, become less elastic, and smaller in cross section due to"O-ring compression set" which occurs when an O-ring seal is exposed toa compression load over time. Such compression loading occurs whenever acap carrying an O-ring seal is installed in a filler neck, Filler neckcap O-ring seals also degrade over time as a result of normal wearfollowing repeated installations and removals of the cap on and from thefiller neck.

Cap 10 is configured to engage filler neck 14 so as to be rotatablefurther in a clockwise direction 120 past the normal fully installedposition shown, for example, in FIGS. 14-17 to compress O-ring seal 34further between cap 10 and annular seat 30 on filler neck 14. Suchfurther compression of O-ring seal 34 during cap installation isdesirable in cases where O-ring seal 34 has changed due to O-ringcompression set and/or has worn due to age and/or use. Cap 10 and fillerneck 14 are designed to allow for rotation of cap 10 relative to fillerneck 14 past the normal fully installed position of cap 10 on fillerneck 14 to compensate for O-ring compression set which occurs when theO-ring is exposed to a load over a period of time and for normal wearfollowing repeated installations and removals of cap 10 on and fromfiller neck 14.

As shown, for example, in FIGS. 18-21, in appropriate cases of the typejust described, handle 18 can be rotated in clockwise direction 120 by auser through angle 134 of, for example, about ten degrees (10°) to causeO-ring seal 34 to be compressed further to assume an effective verticalheight 136 that is less than the effective vertical height 132 of O-ringseal 34 in its normal fully installed position. Such "overtravel" of cap10 in filler neck 14 produces additional desirable O-ring compressionduring cap installation. Although angle 134 is shown in the illustratedembodiment to be about ten degrees (10°), angle 134 can be varied inaccordance with the present invention during cap installation by theuser to create sufficient compression of O-ring seal 34 because nostructural impediment to rotation of cap 10 in direction 120 relative tofiller neck 14 exists in cap 10 and filler neck 14 to block rotation ofcap 10 about axis of rotation 90 through an angle 134 having a magnitudegreat enough to compress O-ring seal 34 sufficiently.

As shown, for example, in FIG. 21, rotation of cap 10 in direction 120causes guide flanges 82 on position-locator lugs 78, 80 to move furtherinto the ramping zone and to slide and cam further on annular inner rims44, 52 of filler neck mounting flanges 38, 40 and causes annular capretainers 94, 112 on cap mounting members 86, 88 to first engage andthen slide and cam on annular inner rims 44, 52 of filler neck mountingflanges 38, 40 in a position trailing the advancing guide flanges 82 onposition-locator lugs 78, 80. As cap 10 rotates about axis of rotation90 during cap installation through an increasing angle 134, the resultis unimpeded engagement of a greater length of annular cap retainers 94,112 on cap mounting members 86, 88 against annular inner rims 44, 52 offiller neck mounting flanges 38, 40 in the vamping zone. As shown, forexample, in FIG. 21, position-locator lugs 78, 80 extend inwardly indirection 122 below cap mounting members 86, 88.

Although the invention has been described in detail with reference tocertain preferred embodiments, variations and modifications exist withinthe scope and spirit of the invention as described and defined in thefollowing claims.

What is claimed is:
 1. A cap for a filler neck having an open mouth andan internal mounting flange mechanism adjacent to the open mouth, thecap comprisinga handle, a body coupled to the handle for rotationtherewith, an annular seal around the body, an external position-locatorlug appended to the body and arranged to lie in spaced-apart relation tothe annular seal, and at least two spiral-shaped cap mounting membersappended to the body to lie in a position between the annular seal andthe external position-locator lug and adapted to engage against theinternal mounting flange mechanism of the filler neck upon installationof the body in the filler neck to retain the cap in the filler neck. 2.The cap of claim 1, wherein one of the at least two spiral-shaped capmounting members has a first end positioned to lie one of adjacent toand in contact with the external position-locator lug.
 3. The cap ofclaim 2, wherein the external position-indicator lug includes aninclined flange guide, the one spiral-shaped cap mounting memberincludes an annular cap retainer facing toward the handle and beingadapted to engage against the internal mounting flange mechanism of thefiller neck upon installation of the body in the filler neck, and theannular cap retainer at the first end of the one spiral-shaped capmounting member is arranged to merge into the inclined flange guide onthe position-locator lug.
 4. The cap of claim 3, wherein the externalposition-locator lug further includes a rounded guide edge dependingfrom the flange guide and extending below the one spiral-shaped capmounting member in a direction away from the handle.
 5. The cap of claim2, wherein the body has a cylindrical exterior surface, the onespiral-shaped cap mounting member is appended to the cylindricalexterior surface, and the one spiral-shaped cap mounting member isformed to include a second end spaced apart from the first end and tohave an arc length along the cylindrical exterior surface characterizedby a central angle of more than sixty degrees.
 6. The cap of claim 5,wherein the central angle is about one hundred sixty degrees.
 7. The capof claim 1, wherein the body has a cylindrical exterior surface and oneof the at least two spiral-shaped cap mounting members is oriented towind helically around the cylindrical exterior surface.
 8. The cap ofclaim 7, wherein the one spiral-shaped cap mounting member has an arclength along the cylindrical interior surface of about one hundred sixtydegrees.
 9. The cap of claim 7, wherein the external position-indicatorlug includes an inclined flange guide facing toward the annular seal andadapted to engage against the internal mounting flange mechanism of thefiller neck to retain the cap in the filler neck.
 10. The cap of claim9, wherein the one spiral-shaped cap mounting member includes an annularcap retainer arranged to face toward the annular seal and positioned tomate with and merge into the inclined flange guide of the externalposition-indicator lug at one end of the one spiral-shaped cap-mountingmember.
 11. The cap of claim 9, wherein the one spiral-shaped capmounting member includes an annular cap retainer arranged to face towardthe annular seal and the annular cap retainer is adapted to engage theinternal mounting flange mechanism of the filler neck along with theinclined flange guide to retain the cap in the filler neck.
 12. The capof claim 9, wherein the one spiral-shaped cap mounting member includesan annular cap supporter arranged to face away from the annular seal andadapted to engage against the internal mounting flange mechanism of thefiller neck during an early stage of cap installation in the fillerneck.
 13. A cap for a filler neck having an open mouth and a pair ofinternal mounting flanges adjacent to the open mouth, the capcomprisinga handle, a body coupled to the handle for rotation therewith,an annular seal positioned to lie around the body, a pair of externalposition-locator lugs appended to the body, and a pair of spiral-shapedcap mounting members appended to the body and arranged to lie in aposition between the annular seal and the pair of externalposition-locator lugs and adapted to engage against the internalmounting flanges of the filler neck upon installation of the body in thefiller neck to retain the cap in the filler neck.
 14. The cap of claim13, wherein the external position-locator lugs are positioned to lieabout one hundred eighty degrees apart from one another incircumferentially spaced-apart relation on a cylindrical exteriorsurface of the body and the pair of spiral-shaped cap mounting membersare appended to the cylindrical exterior surface of the body andoriented to wind spirally around the cylindrical exterior surface in acentral portion of the body located between the annular seal and theunderlying pair of external position-locator lugs.
 15. The cap of claim14, wherein each of the external position-locator lugs includes aninclined flange guide facing toward the annular seal and each of thespiral-shaped cap mounting members includes an annular cap retainerfacing toward the annular seal.
 16. The cap of claim 14, wherein each ofthe spirally shaped cap mounting members has an arc length along thecylindrical exterior surface characterized by a central angle of lessthan one hundred eighty degrees.
 17. The cap of claim 16, wherein thecentral angle is about one hundred sixty degrees.
 18. A closure assemblycomprisinga filler neck having an outer end including a cylindricalinterior side wall and first and second filler neck mounting flangesappended to the cylindrical interior side wall and arranged to definefirst and second lug-receiving spaces therebetween, and a cap includinga cylindrical body sized to fit into the outer end of the filler neck,first and second position-locator lugs appended to the cylindrical bodyand arranged to lie in spaced-apart relation to one another so that eachposition-indicator lug is situated to pass through one of thelug-receiving spaces defined between the first and second filler neckmounting flanges during an initial stage of cap installation in thefiller neck, an annular seal positioned to lie around the cylindricalbody and engage a flange appended to the cylindrical body and an annularouter rim included in the outer end of the filler neck during capinstallation in the filler neck, and first and second spiral-shaped capmounting members appended to the cylindrical body and positioned to liebetween the overlying annular seal and the underlying position-locatorlugs and arranged to engage the first and second filler neck mountingflanges to retain the cap in an installed position in the filler neckand compress the annular seal between the flange appended to thecylindrical body and the annular outer rim included in the filler neck.19. The closure assembly of claim 18, wherein the cylindrical bodyincludes an axially inner end and an axially outer end, the first andsecond position-indicator lugs are appended to the axially inner end,the flange is positioned to lie at the axially outer end, and the firstand second cap mounting members are appended to a central portion of thecylindrical body and positioned to lie between the axially inner andouter ends.
 20. The closure assembly of claim 19, further comprising ahandle including a base coupled to the axially outer end of thecylindrical body and an annular skirt appended to the base and arrangedto surround the flange appended to the cylindrical base and the annularseal arranged to engage the flange.
 21. The closure assembly of claim18, wherein each of the first and second filler neck mounting flanges isspiral-shaped.
 22. The closure assembly of claim 21, wherein each of thefirst and second filler neck mounting flanges is formed to include afirst end and a second end and to have an arc length along thecylindrical interior side wall of the filler neck characterized by acentral angle of about one hundred forty degrees.
 23. The closureassembly of claim 21, wherein each of the spiral-shaped first and secondfiller neck mounting flanges includes a spiral-shaped annular outer rimfacing toward the annular seal and an underlying spiral-shaped annularinner rim facing away from the annular seal.
 24. The closure assembly ofclaim 23, wherein each of the spiral-shaped annular outer rims and thecap mounting members have a pitch and the pitch of each of thespiral-shaped annular outer rims is equivalent to the pitch of each ofthe spiral-shaped cap mounting members to cause each of thespiral-shaped annular outer rims to mate with each of the first andsecond cap mounting members.
 25. The closure assembly of claim 23,wherein each of the spiral-shaped annular inner rims and the capmounting members have a pitch and the pitch of each of the spiral-shapedannular inner rims is equivalent to the pitch of each of thespiral-shaped cap mounting members to cause each of the spiral-shapedannular inner rims to mate with each of the first and second capmounting members.
 26. The closure assembly of claim 21, wherein each ofthe spiral-shaped annular first and second filler neck mounting flangesand the cap mounting members have a pitch and the pitch of each of thespiral-shaped annular first and second filler neck mounting flanges isequivalent to the pitch of each of the spiral-shaped cap mountingmembers to cause each of the spiral-shaped annular first and secondfiller neck mounting flanges to mate with each of the first and secondcap mounting members.
 27. The closure assembly of claim 18, wherein thefirst spiral-shaped cap mounting member has a first end positioned tolie one of adjacent to and in contact with the first position-locatorlug and the second spiral-shaped cap mounting member has a first endpositioned to lie one of adjacent to and in contact with the secondposition-locator lug.
 28. The closure assembly of claim 27, wherein thefirst spiral-shaped cap mounting member has a second end positioned tolie in spaced-apart relation to the second position-locator lug todefine a first space therebetween sized to receive one of the fillerneck mounting flanges therein.
 29. The closure assembly of claim 28,wherein the second spiral-shaped cap mounting member has a second endpositioned to lie in spaced-apart relation to the first position-locatorlug to define a second flange-receiving space therebetween sized toreceive one of the filler neck mounting flanges therein.
 30. A methodfor closing a filler neck having an open mouth, the method comprisingthe steps ofproviding an annular outer rim on the filler neck and firstand second filler neck mounting flanges on a cylindrical interior sidewall of the filler neck in axially inwardly spaced-apart relation fromthe annular outer rim to define a first lug-receiving space betweenfirst ends of the first and second filler neck mounting flanges and asecond lug-receiving space between second ends of the first and secondfiller neck mounting flanges, each of the first and second filler neckmounting flanges being spiral-shaped, providing a cap including a bodysized to fit into the filler neck through the open mouth, an annularseal mounted on the body, first and second position-indicator lugsappended to the body and arranged to lie in spaced-apart relation to oneanother, and first and second cap mounting members appended to the bodyand positioned to lie between the annular seal and the first and secondposition-locator lugs, each of the first and second cap mounting membersbeing spiral-shaped, moving the body of the cap into the filler neck oneof to pass the first and second position-locator lugs through the firstand second lug-receiving spaces and to engage the first and secondposition-locator lugs on the first and second filler neck mountingflanges and guide the first and second position-locator lugs along thefirst and second filler neck mounting flanges until the first and secondposition-locator lugs reach and pass through the first and secondlug-receiving spaces, and then rotating the body in the filler neckabout an axis of rotation to cause the first position-locator lug andcap mounting member to engage an underside of the first filler neckmounting flange and to cause the second position-locator lug and capmounting member to engage an underside of the second filler neckmounting flange so that the annular seal is compressed to establish aliquid fuel and vapor seal between the cap and the filler neck.
 31. Themethod of claim 30, wherein each of the first and second cap mountingmembers has an arc length along the body characterized by a centralangle of about one hundred sixty degrees.